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Kevin C Abbott

Publications and source records attributed to Kevin C Abbott.

At least 55 records · Page 3Linked to original sources
PubMed2003

Thrombotic microangiopathy after renal transplantation in the United States.

BACKGROUND: Analysis of the incidence, time to event, and risk factors for thrombotic microangiopathy (TMA) after renal transplantation (RT), has not been reported in a national population. METHODS: This is a historical cohort study of 15,870 RT recipients in the United States Renal Data System (USRDS) with Medicare as their primary payer between January 1, 1998, and July 31, 2000, followed until December 31, 2000. Patients with Medicare claims with a diagnosis of TMA (International Classification of Diseases, 9th Revision, codes 283.11x or 446.6x) after RT were assessed by Cox regression. RESULTS: Among patients with end-stage renal disease owing to hemolytic uremic syndrome (HUS), 29.2% later had TMA versus 0.8% of patients with ESRD owing to other causes. The incidence of TMA in RT recipients was 5.6 episodes per 1,000 person-years (PY; 189/1,000 PY; for recurrent TMA versus 4.9/1,000 PY for de novo TMA). The risk of TMA was highest for the first 3 months after transplant. Risk factors for de novo TMA included younger recipient age, older donor age, female recipient, and initial use of sirolimus. Patient survival rate after TMA was approximately 50% at 3 years. CONCLUSION: De novo TMA is uncommon and may occur later after RT than previously reported. Risk factors for de novo TMA were also identified.

Adult↗
PubMed2003

Survival by time of day of hemodialysis: analysis of United States Renal Data System Dialysis Morbidity and Mortality Waves III/IV.

BACKGROUND: Whether morning shift hemodialysis is associated with improved survival in comparison to patients receiving afternoon shift hemodialysis has not been shown for a representative sample of US chronic hemodialysis patients. METHODS: We conducted a historical cohort study of a national database (US Renal Data System Dialysis Morbidity and Mortality Waves III/IV) of 6,939 patients who started hemodialysis therapy from January 1, 1990, through December 31, 1993. Patients were followed up through April 9, 2000, and censored at the time of change to a different modality, including transplantation. We estimated the adjusted hazard ratio for all-cause mortality based on the time of day of hemodialysis (0500 to 1200 for morning shift, 1200 to 1800 for afternoon shift, 1800 to midnight for evening shift). Cox regression analysis was used to adjust for other factors associated with survival. RESULTS: For patients aged 60 years and older, the unadjusted 4-year survival rate for patients on morning shift hemodialysis was 28.8% versus 24.1% for patients on afternoon shift hemodialysis and 38.7% for patients on evening shift hemodialysis (P < 0.01 by log-rank test for both versus afternoon shift hemodialysis). Both morning shift (adjusted hazard ratio, 0.90; 95% confidence interval [CI], 0.83 to 0.98; P = 0.02) and evening shift hemodialysis (adjusted hazard ratio, 0.62; 95% CI, 0.48 to 0.80; P < or = 0.001) were independently associated with a lower risk for mortality compared with afternoon shift hemodialysis. No such differences were seen for patients younger than 60 years. Both morning shift and evening shift hemodialysis were independently associated with improved survival compared with afternoon shift hemodialysis in elderly chronic hemodialysis patients. No such association was found for younger patients.

Age Factors↗
PubMed2003

Heart failure as a cause for hospitalization in chronic dialysis patients.

BACKGROUND: Risk factors for heart failure (HF) have not been reported previously in a nationally representative sample of dialysis patients. METHODS: We conducted a historic cohort study of 1,995 patients enrolled in the US Renal Data System Dialysis Morbidity and Mortality Study Wave 2 who were Medicare eligible at the study start and were followed up until December 31, 1999, or receipt of a renal transplant. Cox regression analysis was used to model associations with time to first hospitalization for both recurrent and de novo HF (International Classification of Diseases, Ninth Revision code 428.x), defined as patients with and without a history of HF, respectively. RESULTS: The incidence density of HF was 71/1,000 person-years. Angiotensin-converting enzyme inhibitors and beta-blockers were each used in less than 25% of patients with a known history of HF. A history of coronary heart disease was associated with an increased total risk for HF, as were hemodialysis (versus peritoneal dialysis), aspirin use, and a history of diabetes. However, hemodialysis and aspirin use were the only factors associated with both de novo and recurrent HF. Widened pulse pressure was associated with de novo HF. The mortality rate after HF was 83% at 3 years (adjusted hazard ratio for mortality, 2.10; 95% confidence interval, 1.80 to 2.45; P < 0.0001). CONCLUSION: In chronic dialysis patients, hemodialysis and aspirin use were associated with increased risk for both total and de novo HF. Hospitalized HF was associated with a significantly increased risk for death.

Adrenergic beta-Antagonists↗
PubMed2003

Factors associated with improved short term survival in obese end stage renal disease patients.

PURPOSE: In contrast to its role in the general population, obesity, defined as body mass index (BMI) > or = 30 kg/m(2), has been associated with improved survival in patients with end stage renal disease (ESRD). This apparent benefit has not been explained. METHODS: Using the United States Renal Data System (USRDS), we performed an historical cohort study on 151,027 patients initiated on ESRD therapy between January 1, 1995 and June 30, 1997, who never received renal transplants, and who had information sufficient to calculate BMI. We explored the association of various comorbidities present at the time of dialysis initiation (from HCFA Form 2728) with the presence of obesity by logistic regression, and the association of obesity with patient survival, including specific causes of death, by Cox regression adjusting for factors known to be associated with survival in this population. RESULTS: Obese patients had an unadjusted two-year survival of 68% compared with 58% for non obese patients. Obesity was independently associated with a reduced risk of mortality among chronic dialysis patients (adjusted hazard ratio (AHR) 0.75, 95% confidence interval, 0.72-0.78), after controlling for all comorbidities and risk factors. However, there were significantly adverse interactions among whites (AHR 1.22, 1.14-1.30, across all causes of death) and females (AHR 1.12, 1.04-1.20, entirely due to an increased risk of infectious death). CONCLUSIONS: Obesity in patients presenting with ESRD is associated independently with reduced all cause mortality; however, the relationship is complex and is stronger in African Americans. In addition, subgroup analysis suggests that obesity is associated with increased risk of infectious death in females.

Black or African American↗
PubMed2003

Hospitalized atrial fibrillation after renal transplantation in the United States.

UNLABELLED: Renal transplant recipients have a high incidence of hypertension, a known risk factor for atrial fibrillation (AF), as well as factors that could increase their risk of AF. However, the incidence of, risk factors for, and mortality associated with AF after renal transplantation have not been reported. We present a historical cohort study of 39 628 renal transplant recipients in the United States Renal Data System between 1 July 1994 and 30 June 1998. DATA SOURCE: USRDS files through May 2000. Associations with hospitalizations for a primary diagnosis of AF (ICD-9 codes 427.31) after renal transplant were assessed by Cox Regression analysis. Tacrolimus was not approved for use by the FDA during the time-frame of the study. The incidence of AF after renal transplantation was 5.8 episodes/1000 person-years. In Cox Regression analysis, recipients who were older age, experienced graft loss, rejection, had higher body mass index, renal failure due to hypertension, and cyclosporine use (vs. tacrolimus use) were associated with increased risk of hospitalized AF. Atrial fibrillation was not uncommon after renal transplantation, and was associated with increased risk of mortality, primarily from cardiovascular disease. The strongest risk factors for AF after renal transplantation were older age, allograft rejection, graft loss and obesity.

Atrial Fibrillation↗
PubMed2003

Hospitalized nephrolithiasis after renal transplantation in the United States.

The national incidence of and risk factors for hospitalized nephrolithiasis (NEP) in renal transplant (RT) recipients has not been reported. We conducted a historical cohort study of 42 096 RT recipients in the United States Renal Data System between 1 July 1994 and 30 June 1998. The 1-year incidence of NEP (ICD-9 codes 592.x) after RT in 1997 was compared to the rate of NEP in the general population using the National Hospital Discharge Survey. Associations with time to hospitalizations for a primary diagnosis of nephrolithiasis were assessed by Cox Regression. NEP was uncommon after RT (104 cases per 100 000 person years in 1997). However, females, but not males, had a statistically significant increased risk of NEP compared to the general population (rate ratio for females, 2.84, 95% confidence interval, 2.35-3.58). Kidney stones were more common than ureteral stones, and percutaneous procedures were more common than ureteroscopy or extracorporeal shock wave lithotripsy (ESWL). The only risk factor identified for NEP was renal failure due to stone disease (only one case). NEP was uncommon after RT, but was still more common than in the general population. We identified differences in the presentation and management of NEP after RT in comparison to the general population.

Female↗
PubMed2003

Renal cell carcinoma as a cause of end-stage renal disease in the United States: patient characteristics and survival.

BACKGROUND: The patient characteristics and mortality associated with renal cell carcinoma (RCC) as a cause of end-stage renal disease (ESRD) have not been characterized for a national population. METHODS: An historical cohort study of renal cell carcinoma (RCC) was conducted from April 1, 1995, to December 31, 1999. Included were 360,651 patients in the United States Renal Data System (USRDS) who were initiated on ESRD therapy with valid causes of ESRD. RESULTS: Of the study population, 1646 patients (0.5%) had RCC. The mean age of patients with RCC was 66.8 +/- 14.6 years versus 61.3 +/- 16.4 years for patients with other causes of ESRD (P < 0.01 by Student t test). The unadjusted 3-year survival (censored at the date of renal transplantation) of patients with RCC during the study period was 23% versus 36% in all other patients [adjusted hazard ratio (AHR), 1.10, 95% confidence interval (CI) 1.02-1.19, P = 0.019 by Cox regression]. However, patients with RCC who underwent nephrectomy (bilateral or unilateral) had significantly better survival compared to RCC patients who did not (AHR, 0.73, 95% CI, 0.63-0.85, P < 0.01), and their survival was not significantly different in comparison with nondiabetic ESRD patients. Bilateral nephrectomy (vs. unilateral) was not associated with any difference in adjusted mortality. CONCLUSION: Among patients with ESRD, the demographics of those with RCC were similar to those of patients with RCC in the general population. Overall, patients with RCC had decreased survival compared to patients with other causes of ESRD; those who underwent nephrectomy had significantly better survival than those who did not, with survival comparable to patients with nondiabetic ESRD.

Aged↗
PubMed2003

Impact of renal transplantation on survival in end-stage renal disease patients with elevated body mass index.

BACKGROUND: Cadaveric renal transplantation is associated with a survival advantage compared with dialysis patients remaining on the renal transplantation waiting list, but this advantage has not been confirmed in obese end-stage renal disease (ESRD) patients. METHODS: Using data from the USRDS, we studied 7521 patients who presented with ESRD from 1 April 1995 to 29 June 1999 and later enrolled on the renal transplantation waiting list with body mass indices (BMI) >or=30 kg/m(2) at the time of presentation to ESRD, and followed until 6 November 2000. Recipients of preemptive renal transplantation or organs other than kidneys were excluded. Cox non-proportional hazards regression models were used to calculate adjusted, time-dependent hazard ratios (HR) for time to death in a given patient during the study period, controlling for renal transplantation, demographics and comorbidities (Form 2728). RESULTS: The incidence of mortality was 3.3 episodes per 100 patient-years (PY) in cadaveric renal transplantation and 1.9/100 PY in living donor renal transplantation compared with 6.6 episodes/100 PY in all patients on the transplant waiting list. In comparison to maintenance dialysis, both recipients of solitary cadaveric kidneys (HR 0.39, 95% CI 0.33 to 0.47), and recipients of living donor kidneys (HR 0.23, 95% CI 0.16 to 0.34) had statistically significant improved survival. A benefit of cadaveric renal transplantation did not apply to patients with BMI >or=41 kg/m(2) (HR 0.47, 95% CI, 0.17 to 1.25, P = 0.13). CONCLUSIONS: Obese patients on the renal transplant waiting list had a significantly lower risk of mortality after renal transplantation compared with those remaining on dialysis.

Adult↗
PubMed2003

Hospitalized psychoses after renal transplantation in the United States: incidence, risk factors, and prognosis.

Although it is recommended that renal transplant (RT) candidates routinely undergo screening for mental health-related conditions, national statistics for psychoses after RT have not been reported. This is a historical cohort study of 39,628 renal transplant recipients in the United States Renal Data System between July 1, 1994, and June 30, 1998, and followed until December 31, 1999. Adjusted hazard ratios (AHR) for time to hospitalization for both a primary and secondary discharge diagnosis of psychoses (ICD-9 codes 290.x-299.x) after RT and mortality/graft loss after psychosis were assessed by Cox Regression. In addition, rates of psychosis were compared with 178,986 patients with Medicare as their primary payer who started chronic dialysis from April 1, 1995, to June 29, 1999. The incidence of psychoses was 7.5/1000 person-years (PY) after RT compared with 7.2/1000 PY for all patients on chronic dialysis and 9.6/1000 PY for dialysis patients aged 65 yr or younger. Among RT recipients, graft loss (AHR, 2.97; 95% CI, 2.19 to 4.02), allograft rejection, and cadaveric donation were independently associated with psychosis, which was associated with an increased risk of both death (AHR, 2.09; 95% CI, 1.71 to 2.56; P < 0.001) and graft loss (AHR, 1.79; 95% CI, 1.15 to 2.78; P = 0.01). Graft loss due to noncompliance was significantly more common after psychosis (9.0% versus 3.7% in patients not hospitalized for psychosis; P < 0.001). The incidence of hospitalized psychosis was not substantially higher after RT compared with chronic dialysis patients. Psychoses were independently associated with increased risk of death and graft loss after renal transplantation, possibly mediated through medical non-adherence.

Adult↗
PubMed2003

Early renal insufficiency and hospitalized heart disease after renal transplantation in the era of modern immunosuppression.

Renal insufficiency has been identified as a risk factor for graft loss and death after renal transplantation but has not been consistently linked to early, nonfatal, hospitalized heart disease (HHD). With the United States Renal Data System database, 29,597 patients who received a kidney transplant between January 1, 1996, and July 31, 2000, with Medicare as the primary payer, and were monitored until December 31, 2000, were studied. Cox proportional-hazards regression models were used to calculate the association of recipient estimated GFR (eGFR) at 1 yr after renal transplantation, as determined with the Modification of Diet in Renal Disease formula, with hospitalization for treatment of acute coronary syndromes (ACS) (International Classification of Diseases, version 9, code 410.x or 411.x) or congestive heart failure (CHF) (code 428.x) 1 to 3 yr after renal transplantation. Rates of ACS and CHF were 2.2 and 4.9%, respectively, for patients with eGFR of <44.8 ml/min per 1.73 m(2), compared with 1.2 and 1.4% for patients with eGFR of >69.7 ml/min per 1.73 m(2). Reduced eGFR (<44.8 ml/min per 1.73 m(2), compared with >69.7 ml/min per 1.73 m(2)) at the end of the first 1 yr after transplantation was independently associated with increased risks of both ACS (adjusted hazard ratio, 2.16; 95% confidence interval, 1.39 to 3.35) and CHF (adjusted hazard ratio, 2.95; 95% confidence interval, 2.24 to 3.90). It was concluded that early renal insufficiency (approximately stage 3 chronic kidney disease) was associated with higher rates of HHD 1 to 3 yr after kidney transplantation. Preservation of renal function after renal transplantation may reduce the rates of HHD, and renal transplant recipients with reduced eGFR should be considered at high risk of developing cardiovascular disease.

Adult↗
PubMed2003

Hepatitis C and renal transplantation in the era of modern immunosuppression.

Kidneys from donors who are positive for hepatitis C virus (DHCV+) have recently been identified as an independent risk factor for mortality after renal transplantation. However, it has not been determined whether risk persists after adjustment for baseline cardiac comorbidity or applies in the era of modern immunosuppression. Therefore, a historical cohort study was conducted of US adult cadaveric renal transplant recipients from January 1, 1996, to May 31, 2001; followed until October 31, 2001. A total of 36,956 patients had valid donor and recipient HCV serology. Cox regression analysis was used to model adjusted hazard ratios for mortality and graft loss, respectively, adjusted for other factors, including comorbid conditions from Center for Medicare and Medicaid Studies Form 2728 and previous dialysis access-related complications. It was found that DHCV+ was independently associated with an increased risk of mortality (adjusted hazard ratio, 2.12, 95% confidence interval, 1.72 to 2.87; P < 0.001), primarily as a result of infection. Mycophenolate mofetil was associated with improved survival in DHCV+ patients, primarily related to fewer infectious deaths. Adjusted analyses limited to recipients who were HCV+, HCV negative, or age 65 and over, or by use of mycophenolate mofetil confirmed that DHCV+ was independently associated with mortality in each subgroup. It is concluded that DHCV+ is independently associated with an increased risk of mortality after renal transplantation adjusted for baseline comorbid conditions in all subgroups. Recipients of DHCV+ organs should be considered at high risk for excessive immunosuppression.

Adolescent↗
PubMed2003

Walter Reed Army Medical Center's Internet-based electronic health portal.

BACKGROUND: Use of the World Wide Web (WWW) and electronic media to facilitate medical care has been the subject of many reports in the popular press. However, few reports have documented the results of implementing electronic health portals for essential medical tasks, such as prescription refills and appointments. METHODS: At Walter Reed Army Medical Center, "Search & Learn" medical information, Internet-based prescription refills and patient appointments were established in January 2001. A multiphase retrospective analysis was conducted to determine the use of the "Search & Learn" medical information and the relative number of prescription refills and appointments conducted via the WWW compared with conventional methods. RESULTS: From January 2001 to May 2002, there were 34,741 refills and 819 appointments made over the Internet compared with 2,275,112 refills and approximately 500,000 appointments made conventionally. WWW activity accounted for 1.52% of refills and 0.16% of appointments. There was a steady increase in this percentage over the time of the analysis. In April of 2002, the monthly average of online refills had risen to 4.57% and online appointments were at 0.27%. Online refills were projected to account for 10% of all prescriptions in 2 years. The "Search & Learn" medical information portion of our web site received 147,429 unique visits during this same time frame, which was an average of 326 visitors per day. CONCLUSIONS: WWW-based methods of conducting essential medical tasks accounted for a small but rapidly increasing percentage of total activity at Walter Reed Army Medical Center. Subsequent phases of analysis will assess demographic and geographic factors and aid in the design of future systems to increase use of the Internet-based systems.

Appointments and Schedules↗
PubMed2002

Hospitalized poisonings after renal transplantation in the United States.

BACKGROUND: The national incidence of and risk factors for hospitalized poisonings in renal transplant recipients has not been reported. METHODS: Historical cohort study of 39,628 renal transplant recipients in the United States Renal Data System between 1 July 1994 and 30 June 1998. Associations with time to hospitalizations for a primary diagnosis of poisonings (ICD-9 codes 960.x-989.x) within three years after renal transplant were assessed by Cox Regression. RESULTS: The incidence of hospitalized poisonings was 2.3 patients per 1000 person years. The most frequent causes of poisonings were immunosuppressive agents (25.3%), analgesics/antipyretics (14.1%), psychotropic agents (10.0%), and insulin/antidiabetic agents (7.1%). In Cox Regression analysis, low body mass index (BMI, <21.6 vs. >28.3 kg/m2, adjusted hazard ratio (AHR), 3.02, 95% CI, 1.45-6.28, and allograft rejection, AHR 1.83, 95% CI, 1.15-2.89, were the only factors independently associated with hospitalized poisonings. Hospitalized poisonings were independently associated with increased mortality (AHR, 1.54, 95% CI 1.22-1.92, p = 0.002). CONCLUSIONS: Hospitalized poisonings were associated with increased mortality after renal transplantation. However, almost all reported poisonings in renal transplant recipients were due to the use of prescribed medications. Allograft rejection and low BMI were the only independent risk factors for poisonings identified in this population.

Adult↗
PubMed2002

A multidisciplinary program for achieving lipid goals in chronic hemodialysis patients.

BACKGROUND: There is little information on how target lipid levels can be achieved in end stage renal disease (ESRD) patients in a systematic, multidisciplinary fashion. METHODS: We retrospectively reviewed a pharmacist-directed hyperlipidemia management program for chronic hemodialysis (HD) patients. All 26 adult patients on chronic HD at a tertiary care medical facility were entered into the program. A clinical pharmacist was responsible for laboratory monitoring, patient counseling, and the initiation and dosage adjustment of an appropriate 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase inhibitor (statin) using a dosing algorithm and monitoring guidelines. The low-density lipoprotein (LDL) cholesterol goal was leq; 100 mg/dl. A renal dietitian provided nutrition counseling and the nephrologist was notified of potential or existing drug interactions or adverse drug reactions (ADRs). Patients received a flyer containing lipid panel results to encourage compliance. Data was collected at program initiation and for 6 months thereafter. RESULTS: At the start of the program, 58% of patients were at target LDL cholesterol. At 6 months, 88% had achieved target LDL (p = 0.015). Mean LDL cholesterol decreased from 96 +/- 5 to 80 +/- 3 mg/dl (p < 0.01), and mean total cholesterol decreased from 170 +/- 7 to 151 +/- 4 mg/dl (p < 0.01). Fifteen adjustments in drug therapy were made. Eight adverse drug reactions were identified; 2 required drug discontinuation or an alternative agent. Physicians were alerted to 8 potential drug-drug interactions, and appropriate monitoring was performed. CONCLUSIONS: Our findings demonstrate both feasibility and efficacy of a multidisciplinary approach in management of hyperlipidemia in HD patients.

Algorithms↗
PubMed2002

Polycystic kidney disease in patients on the renal transplant waiting list: trends in hematocrit and survival.

BACKGROUND: The patient characteristics and mortality associated with autosomal dominant polycystic kidney disease (PKD) have not been characterized for a national sample of end stage renal disease (ESRD) patients on the renal transplant waiting list. METHODS: 40,493 patients in the United States Renal Data System who were initiated on ESRD therapy between 1 April 1995 and 29 June 1999 and later enrolled on the renal transplant waiting list were analyzed in an historical cohort study of the relationship between hematocrit at the time of presentation to ESRD and survival (using Cox Regression) in patients with PKD as a cause of ESRD. RESULTS: Hematocrit levels at presentation to ESRD increased significantly over more recent years of the study. Hematocrit rose in parallel in patients with and without PKD, but patients with PKD had consistently higher hemoglobin. PKD was independently associated with higher hematocrit in multiple linear regression analysis (p < 0.0001). In logistic regression, higher hematocrit was independently associated with PKD. In Cox Regression analysis, PKD was associated with statistically significant improved survival both in comparison with diabetic (hazard ratio, 0.64, 95% CI 0.53-0.77, p < 0.001) and non-diabetic (HR 0.68, 95% CI 0.56-0.82, p = 0.001) ESRD patients, adjusted for all other factors. CONCLUSIONS: Hematocrit at presentation to ESRD was significantly higher in patients with PKD compared with patients with other causes of ESRD. The survival advantage of PKD in ESRD persisted even adjusted for differences in hematocrit and in comparison with patients on the renal transplant waiting list.

Female↗